A turbine type combustion engine generates hot gasses which are directed by nozzles to turn turbine wheel(s) in the turbine engine. The wheel(s) of the turbine engine are coupled to mechanical apparatus to cause movement thereof.
Such a turbine engine may also be used, for example, in torpedoes wherein a propellant is provided to generate hot gasses for driving the wheel(s) of the turbine engine. The wheel(s) of the turbine engine are coupled to the shaft of the propeller of the torpedo, thereby rotating the propeller through the shaft so as to propel the torpedo.
The turbine engine of a torpedo operates with a fixed amount of propellant which is ignited to generate the hot gasses for turning the wheel(s) of the turbine engine. Most torpedoes, whether launched from a submarine or air, run at a medium speed range which is called the search mode for the majority of a run and upon acquisition of the target goes to a high speed range for the duration of the run. In order to maximize the range of the torpedo and/or increase the search mode time, it is necessary that the efficiency of the turbine engine be maintained at a high level at both the medium speed and the high speed ranges.
Turbine engines for torpedoes are generally designed for maximum efficiency corresponding to the high speed because the largest amount of fuel is consumed at the high speed. Maintaining high efficiency in the turbine engine at both the medium speed and the high speed ranges requires maintaining the pressure ratio across the nozzle(s) of the turbine engine at approximately the same level at both the medium speed and high speed ranges. Switching from the medium speed range to the high speed range requires an increase in the flow of hot gases through the nozzle(s) to cause the wheel(s) of the turbine engine to rotate at a faster rate. This increase in the flow of hot gases through the nozzle(s) causes an increase in the pressure ratio across the nozzle(s). A lower efficiency results when operating at the lower pressure ratios of the medium speed range. This decrease in the pressure ratio occurs because when the turbine engine is operated at the medium speed range the decrease in the flow of hot gasses causes a decrease in pressure at the inlet.
Various torpedo control systems and control systems for controlling turbines are known in the art. However, none of the systems address the problem of maintaining high efficiency in the turbine by maintaining the same pressure ratio across the nozzles of the turbine at all speed ranges.
For example, U.S. Pat. No. 2,974,619 discloses a fluid control system for controlling the operation of combustion apparatus in the firing cycle of a torpedo. Particularly, U.S. Pat. No. 2,974,619 discloses a fluid control system for controlling the introduction of combustion materials to prevent pre-ignition and to ensure ignition at the proper time.
The apparatus disclosed by U.S. Pat. No. 2,974,619 does not address the problems associated with maintaining high efficiency in a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S Pat. No. 3,045,624 discloses a speed change system for use in torpedoes of the type propelled by an electric battery source of energy.
U.S. Pat. No. 3,045,624 is not directed to torpedoes powered by a turbine engine. Further U.S. Pat. No. 3,045,624 does not address the problems associated with maintaining high efficiency in a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S Pat. No. 3,417,719 discloses adaptor apparatus for an underwater projectile for precisely propelling the projectile along a predetermined path by permitting a stream of gasses to flow from the casing of the projectile.
U.S Pat. No. 3,417,719 is not directed to turbine engines. Therefore, U.S. Pat. No. 3,417,719 does not address the problems associated with maintaining high efficiency in a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S Pat. No. 3,990,230 discloses a method for controlling a steam turbine in a composite plant equipped with steam and gas turbines wherein steam produced by utilizing exhaust gas from the gas turbine is controlled according to the speed of the steam turbine and the condition of the steam fed to the steam turbine.
U.S. Pat. No. 3,990,230 although directed to improvements in the operation of turbine engines does not address the problems associated with maintaining high efficiency in a gas turbine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S. Pat. No. 4,145,875 discloses apparatus for improving the rate of gas flow in gas turbine engines, turbo chargers or superchargers by providing individual gate elements reciprocally mounted to open and close separate divergent diffuser passages for centrifugal compressors or radial inflow turbine nozzle assemblies.
U.S Pat. No. 4,145,875 although directed to improving the fuel economy of a gas turbine engine does not adequately address all the issues related to improving the efficiency of a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S. Pat. No. 4,648,242 discloses apparatus used for controlling the function of a fuel powered turbine engine by providing a constant fuel consumption rate.
Although U.S. Pat. No. 4,648,242 is directed to improving the efficiency of a turbine engine, U.S. Pat. No. 4,648,242 does not adequately address all the issues related to improving the efficiency of a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S. Pat. No. 4,648,322 discloses a propulsion and directional control mechanism for an underwater device such as torpedo. U.S. Pat. No. 4,648,322 makes use of a gas turbine engine for the propulsion system.
Although U.S. Pat. No. 4,648,322 is directed to improvements in the turbine engine and the directional control mechanism U.S. Pat. No. 4,648,322 does not adequately address all the issues related to improving the efficiency of a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.
U.S. Pat. No. 4,672,806 discloses turbine engine fuel control apparatus for regulating the amount of fuel supplied to the turbine engine in response to parameters which include engine acceleration U.S. Pat. No. 4,672,806 regulates the amount of fuel supplied to the turbine engine by electrical apparatus which outputs an electrical signal which controls the appropriate value in the system.
U.S. Pat. No. 4,672,806 does not address the problems associated with improving the efficiency of a turbine engine by maintaining the same pressure ratio across the nozzles at all speed ranges.